PosixCondition.hpp

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/*
 * PosixCondition.hpp
 *
 * Copyright (C) 2012 Evidence Srl - www.evidence.eu.com
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
 */

#ifndef POSIXCONDITION_HPP_
#define POSIXCONDITION_HPP_

#include "PosixMutex.hpp"
#include "Time.hpp"


#include <pthread.h>
#include <time.h>

namespace onposix {

/**
 * \brief Implementation of a condition variable.
 *
 * The class is non copyable and makes use of the pthread library.
 */
class PosixCondition {

        PosixCondition(const PosixMutex&);
        PosixCondition& operator=(const PosixMutex&);

        pthread_cond_t cond_;

public:
        PosixCondition();
        ~PosixCondition();

        /**
         * \brief Blocks the calling thread on the condition variable.
         *
         * These functions atomically release mutex and cause the calling thread
         * to block on the condition variable.
         * @param m Mutex released when blocking and acquired when unblocking.
         * @return 0 in case of success
         */
        int wait(PosixMutex* m) {
                return pthread_cond_wait(&cond_, &(m->mutex_));
        }

        /**
         * \brief Blocks the calling thread on the condition variable.
         *
         * These functions atomically release mutex and cause the calling thread
         * to block on the condition variable.
         * @param m Mutex released when blocking and acquired when unblocking.
         * @param abstime Absolute time for timeout
         * @return 0 in case of success, ETIMEDOUT in case of timeout
         */
        int timedWait(PosixMutex* m, const Time& abstime) {
                timespec ts;
                ts.tv_sec = abstime.getSeconds();
                ts.tv_nsec = abstime.getNSeconds();
                return pthread_cond_timedwait(&cond_, &(m->mutex_), &ts);
        }

        /**
         * \brief Unblocks at least one of the blocked threads.
         *
         * @return 0 in case of success
         */
        int signal() {
                return pthread_cond_signal(&cond_);
        }

        /**
         * \brief Unblocks all blocked threads.
         *
         * @return 0 in case of success
         */
        int signalAll() {
                return pthread_cond_broadcast(&cond_);
        }
};



} /* onposix */

#endif /* POSIXCONDITION_HPP_ */